[FFmpeg-devel] [PATCH 07/11] avutil/half2float: move tables to header-internal structs

Timo Rothenpieler timo at rothenpieler.org
Wed Aug 10 23:47:08 EEST 2022


Having to put the knowledge of the size of those arrays into a multitude
of places is rather smelly.
---
 libavcodec/exr.c       | 27 ++++++++--------------
 libavcodec/exrenc.c    | 11 +++++----
 libavcodec/pnm.h       |  5 ++---
 libavcodec/pnmdec.c    | 42 ++++++++--------------------------
 libavcodec/pnmenc.c    | 13 +++++------
 libavutil/float2half.h | 51 +++++++++++++++++++++++-------------------
 libavutil/half2float.h | 46 ++++++++++++++++++++-----------------
 7 files changed, 84 insertions(+), 111 deletions(-)

diff --git a/libavcodec/exr.c b/libavcodec/exr.c
index 47f4786491..825354873d 100644
--- a/libavcodec/exr.c
+++ b/libavcodec/exr.c
@@ -191,9 +191,7 @@ typedef struct EXRContext {
     float gamma;
     union av_intfloat32 gamma_table[65536];
 
-    uint32_t mantissatable[3072];
-    uint32_t exponenttable[64];
-    uint16_t offsettable[64];
+    half2float_tables h2f_tables;
 } EXRContext;
 
 static int zip_uncompress(const EXRContext *s, const uint8_t *src, int compressed_size,
@@ -899,10 +897,7 @@ static int ac_uncompress(const EXRContext *s, GetByteContext *gb, float *block)
             n += val & 0xff;
         } else {
             ret = n;
-            block[ff_zigzag_direct[n]] = av_int2float(half2float(val,
-                                                      s->mantissatable,
-                                                      s->exponenttable,
-                                                      s->offsettable));
+            block[ff_zigzag_direct[n]] = av_int2float(half2float(val, &s->h2f_tables));
             n++;
         }
     }
@@ -1120,8 +1115,7 @@ static int dwa_uncompress(const EXRContext *s, const uint8_t *src, int compresse
                 uint16_t *dc = (uint16_t *)td->dc_data;
                 union av_intfloat32 dc_val;
 
-                dc_val.i = half2float(dc[idx], s->mantissatable,
-                                      s->exponenttable, s->offsettable);
+                dc_val.i = half2float(dc[idx], &s->h2f_tables);
 
                 block[0] = dc_val.f;
                 ac_uncompress(s, &agb, block);
@@ -1171,7 +1165,7 @@ static int dwa_uncompress(const EXRContext *s, const uint8_t *src, int compresse
         for (int x = 0; x < td->xsize; x++) {
             uint16_t ha = ai0[x] | (ai1[x] << 8);
 
-            ao[x] = half2float(ha, s->mantissatable, s->exponenttable, s->offsettable);
+            ao[x] = half2float(ha, &s->h2f_tables);
         }
     }
 
@@ -1427,10 +1421,7 @@ static int decode_block(AVCodecContext *avctx, void *tdata,
                         }
                     } else {
                         for (x = 0; x < xsize; x++) {
-                            ptr_x[0].i = half2float(bytestream_get_le16(&src),
-                                                    s->mantissatable,
-                                                    s->exponenttable,
-                                                    s->offsettable);
+                            ptr_x[0].i = half2float(bytestream_get_le16(&src), &s->h2f_tables);
                             ptr_x++;
                         }
                     }
@@ -2217,7 +2208,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
     float one_gamma = 1.0f / s->gamma;
     avpriv_trc_function trc_func = NULL;
 
-    half2float_table(s->mantissatable, s->exponenttable, s->offsettable);
+    init_half2float_tables(&s->h2f_tables);
 
     s->avctx              = avctx;
 
@@ -2230,18 +2221,18 @@ static av_cold int decode_init(AVCodecContext *avctx)
     trc_func = avpriv_get_trc_function_from_trc(s->apply_trc_type);
     if (trc_func) {
         for (i = 0; i < 65536; ++i) {
-            t.i = half2float(i, s->mantissatable, s->exponenttable, s->offsettable);
+            t.i = half2float(i, &s->h2f_tables);
             t.f = trc_func(t.f);
             s->gamma_table[i] = t;
         }
     } else {
         if (one_gamma > 0.9999f && one_gamma < 1.0001f) {
             for (i = 0; i < 65536; ++i) {
-                s->gamma_table[i].i = half2float(i, s->mantissatable, s->exponenttable, s->offsettable);
+                s->gamma_table[i].i = half2float(i, &s->h2f_tables);
             }
         } else {
             for (i = 0; i < 65536; ++i) {
-                t.i = half2float(i, s->mantissatable, s->exponenttable, s->offsettable);
+                t.i = half2float(i, &s->h2f_tables);
                 /* If negative value we reuse half value */
                 if (t.f <= 0.0f) {
                     s->gamma_table[i] = t;
diff --git a/libavcodec/exrenc.c b/libavcodec/exrenc.c
index 56c084d483..6ab9400b7c 100644
--- a/libavcodec/exrenc.c
+++ b/libavcodec/exrenc.c
@@ -87,15 +87,14 @@ typedef struct EXRContext {
 
     EXRScanlineData *scanline;
 
-    uint16_t basetable[512];
-    uint8_t shifttable[512];
+    float2half_tables f2h_tables;
 } EXRContext;
 
 static av_cold int encode_init(AVCodecContext *avctx)
 {
     EXRContext *s = avctx->priv_data;
 
-    float2half_tables(s->basetable, s->shifttable);
+    init_float2half_tables(&s->f2h_tables);
 
     switch (avctx->pix_fmt) {
     case AV_PIX_FMT_GBRPF32:
@@ -256,7 +255,7 @@ static int encode_scanline_rle(EXRContext *s, const AVFrame *frame)
                 const uint32_t *src = (const uint32_t *)(frame->data[ch] + y * frame->linesize[ch]);
 
                 for (int x = 0; x < frame->width; x++)
-                    dst[x] = float2half(src[x], s->basetable, s->shifttable);
+                    dst[x] = float2half(src[x], &s->f2h_tables);
             }
             break;
         }
@@ -324,7 +323,7 @@ static int encode_scanline_zip(EXRContext *s, const AVFrame *frame)
                     const uint32_t *src = (const uint32_t *)(frame->data[ch] + (y * s->scanline_height + l) * frame->linesize[ch]);
 
                     for (int x = 0; x < frame->width; x++)
-                        dst[x] = float2half(src[x], s->basetable, s->shifttable);
+                        dst[x] = float2half(src[x], &s->f2h_tables);
                 }
             }
             break;
@@ -482,7 +481,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                     const uint32_t *src = (const uint32_t *)(frame->data[ch] + y * frame->linesize[ch]);
 
                     for (int x = 0; x < frame->width; x++)
-                        bytestream2_put_le16(pb, float2half(src[x], s->basetable, s->shifttable));
+                        bytestream2_put_le16(pb, float2half(src[x], &s->f2h_tables));
                 }
             }
         }
diff --git a/libavcodec/pnm.h b/libavcodec/pnm.h
index 7e5445f529..25251d9e4a 100644
--- a/libavcodec/pnm.h
+++ b/libavcodec/pnm.h
@@ -22,6 +22,7 @@
 #ifndef AVCODEC_PNM_H
 #define AVCODEC_PNM_H
 
+#include "libavutil/half2float.h"
 #include "avcodec.h"
 
 typedef struct PNMContext {
@@ -34,9 +35,7 @@ typedef struct PNMContext {
     int half;
     float scale;
 
-    uint32_t mantissatable[3072];
-    uint32_t exponenttable[64];
-    uint16_t offsettable[64];
+    half2float_tables h2f_tables;
 } PNMContext;
 
 int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s);
diff --git a/libavcodec/pnmdec.c b/libavcodec/pnmdec.c
index 9383dc8e60..6adc348ec8 100644
--- a/libavcodec/pnmdec.c
+++ b/libavcodec/pnmdec.c
@@ -313,18 +313,9 @@ static int pnm_decode_frame(AVCodecContext *avctx, AVFrame *p,
                 b = (float *)p->data[1];
                 for (int i = 0; i < avctx->height; i++) {
                     for (int j = 0; j < avctx->width; j++) {
-                        r[j] = av_int2float(half2float(AV_RL16(s->bytestream+0),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
-                        g[j] = av_int2float(half2float(AV_RL16(s->bytestream+2),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
-                        b[j] = av_int2float(half2float(AV_RL16(s->bytestream+4),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
+                        r[j] = av_int2float(half2float(AV_RL16(s->bytestream+0), &s->h2f_tables)) * scale;
+                        g[j] = av_int2float(half2float(AV_RL16(s->bytestream+2), &s->h2f_tables)) * scale;
+                        b[j] = av_int2float(half2float(AV_RL16(s->bytestream+4), &s->h2f_tables)) * scale;
                         s->bytestream += 6;
                     }
 
@@ -340,18 +331,9 @@ static int pnm_decode_frame(AVCodecContext *avctx, AVFrame *p,
                 b = (float *)p->data[1];
                 for (int i = 0; i < avctx->height; i++) {
                     for (int j = 0; j < avctx->width; j++) {
-                        r[j] = av_int2float(half2float(AV_RB16(s->bytestream+0),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
-                        g[j] = av_int2float(half2float(AV_RB16(s->bytestream+2),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
-                        b[j] = av_int2float(half2float(AV_RB16(s->bytestream+4),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
+                        r[j] = av_int2float(half2float(AV_RB16(s->bytestream+0), &s->h2f_tables)) * scale;
+                        g[j] = av_int2float(half2float(AV_RB16(s->bytestream+2), &s->h2f_tables)) * scale;
+                        b[j] = av_int2float(half2float(AV_RB16(s->bytestream+4), &s->h2f_tables)) * scale;
                         s->bytestream += 6;
                     }
 
@@ -394,10 +376,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, AVFrame *p,
                 float *g = (float *)p->data[0];
                 for (int i = 0; i < avctx->height; i++) {
                     for (int j = 0; j < avctx->width; j++) {
-                        g[j] = av_int2float(half2float(AV_RL16(s->bytestream),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
+                        g[j] = av_int2float(half2float(AV_RL16(s->bytestream), &s->h2f_tables)) * scale;
                         s->bytestream += 2;
                     }
                     g += p->linesize[0] / 4;
@@ -406,10 +385,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, AVFrame *p,
                 float *g = (float *)p->data[0];
                 for (int i = 0; i < avctx->height; i++) {
                     for (int j = 0; j < avctx->width; j++) {
-                        g[j] = av_int2float(half2float(AV_RB16(s->bytestream),
-                                                       s->mantissatable,
-                                                       s->exponenttable,
-                                                       s->offsettable)) * scale;
+                        g[j] = av_int2float(half2float(AV_RB16(s->bytestream), &s->h2f_tables)) * scale;
                         s->bytestream += 2;
                     }
                     g += p->linesize[0] / 4;
@@ -501,7 +477,7 @@ static av_cold int phm_dec_init(AVCodecContext *avctx)
 {
     PNMContext *s = avctx->priv_data;
 
-    half2float_table(s->mantissatable, s->exponenttable, s->offsettable);
+    init_half2float_tables(&s->h2f_tables);
 
     return 0;
 }
diff --git a/libavcodec/pnmenc.c b/libavcodec/pnmenc.c
index 7ce534d06e..70992531bf 100644
--- a/libavcodec/pnmenc.c
+++ b/libavcodec/pnmenc.c
@@ -30,8 +30,7 @@
 #include "encode.h"
 
 typedef struct PHMEncContext {
-    uint16_t basetable[512];
-    uint8_t shifttable[512];
+    float2half_tables f2h_tables;
 } PHMEncContext;
 
 static int pnm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
@@ -169,9 +168,9 @@ static int pnm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 
         for (int i = 0; i < avctx->height; i++) {
             for (int j = 0; j < avctx->width; j++) {
-                AV_WN16(bytestream + 0, float2half(av_float2int(r[j]), s->basetable, s->shifttable));
-                AV_WN16(bytestream + 2, float2half(av_float2int(g[j]), s->basetable, s->shifttable));
-                AV_WN16(bytestream + 4, float2half(av_float2int(b[j]), s->basetable, s->shifttable));
+                AV_WN16(bytestream + 0, float2half(av_float2int(r[j]), &s->f2h_tables));
+                AV_WN16(bytestream + 2, float2half(av_float2int(g[j]), &s->f2h_tables));
+                AV_WN16(bytestream + 4, float2half(av_float2int(b[j]), &s->f2h_tables));
                 bytestream += 6;
             }
 
@@ -184,7 +183,7 @@ static int pnm_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
 
         for (int i = 0; i < avctx->height; i++) {
             for (int j = 0; j < avctx->width; j++) {
-                AV_WN16(bytestream, float2half(av_float2int(g[j]), s->basetable, s->shifttable));
+                AV_WN16(bytestream, float2half(av_float2int(g[j]), &s->f2h_tables));
                 bytestream += 2;
             }
 
@@ -295,7 +294,7 @@ static av_cold int phm_enc_init(AVCodecContext *avctx)
 {
     PHMEncContext *s = avctx->priv_data;
 
-    float2half_tables(s->basetable, s->shifttable);
+    init_float2half_tables(&s->f2h_tables);
 
     return 0;
 }
diff --git a/libavutil/float2half.h b/libavutil/float2half.h
index d6aaab8278..9252560649 100644
--- a/libavutil/float2half.h
+++ b/libavutil/float2half.h
@@ -21,45 +21,50 @@
 
 #include <stdint.h>
 
-static void float2half_tables(uint16_t *basetable, uint8_t *shifttable)
+typedef struct float2half_tables {
+    uint16_t basetable[512];
+    uint8_t shifttable[512];
+} float2half_tables;
+
+static void init_float2half_tables(float2half_tables *t)
 {
     for (int i = 0; i < 256; i++) {
         int e = i - 127;
 
         if (e < -24) { // Very small numbers map to zero
-            basetable[i|0x000]  = 0x0000;
-            basetable[i|0x100]  = 0x8000;
-            shifttable[i|0x000] = 24;
-            shifttable[i|0x100] = 24;
+            t->basetable[i|0x000]  = 0x0000;
+            t->basetable[i|0x100]  = 0x8000;
+            t->shifttable[i|0x000] = 24;
+            t->shifttable[i|0x100] = 24;
         } else if (e < -14) { // Small numbers map to denorms
-            basetable[i|0x000] = (0x0400>>(-e-14));
-            basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000;
-            shifttable[i|0x000] = -e-1;
-            shifttable[i|0x100] = -e-1;
+            t->basetable[i|0x000] = (0x0400>>(-e-14));
+            t->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000;
+            t->shifttable[i|0x000] = -e-1;
+            t->shifttable[i|0x100] = -e-1;
         } else if (e <= 15) { // Normal numbers just lose precision
-            basetable[i|0x000] = ((e + 15) << 10);
-            basetable[i|0x100] = ((e + 15) << 10) | 0x8000;
-            shifttable[i|0x000] = 13;
-            shifttable[i|0x100] = 13;
+            t->basetable[i|0x000] = ((e + 15) << 10);
+            t->basetable[i|0x100] = ((e + 15) << 10) | 0x8000;
+            t->shifttable[i|0x000] = 13;
+            t->shifttable[i|0x100] = 13;
         } else if (e < 128) { // Large numbers map to Infinity
-            basetable[i|0x000]  = 0x7C00;
-            basetable[i|0x100]  = 0xFC00;
-            shifttable[i|0x000] = 24;
-            shifttable[i|0x100] = 24;
+            t->basetable[i|0x000]  = 0x7C00;
+            t->basetable[i|0x100]  = 0xFC00;
+            t->shifttable[i|0x000] = 24;
+            t->shifttable[i|0x100] = 24;
         } else { // Infinity and NaN's stay Infinity and NaN's
-            basetable[i|0x000]  = 0x7C00;
-            basetable[i|0x100]  = 0xFC00;
-            shifttable[i|0x000] = 13;
-            shifttable[i|0x100] = 13;
+            t->basetable[i|0x000]  = 0x7C00;
+            t->basetable[i|0x100]  = 0xFC00;
+            t->shifttable[i|0x000] = 13;
+            t->shifttable[i|0x100] = 13;
         }
     }
 }
 
-static uint16_t float2half(uint32_t f, uint16_t *basetable, uint8_t *shifttable)
+static uint16_t float2half(uint32_t f, const float2half_tables *t)
 {
     uint16_t h;
 
-    h = basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> shifttable[(f >> 23) & 0x1ff]);
+    h = t->basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> t->shifttable[(f >> 23) & 0x1ff]);
 
     return h;
 }
diff --git a/libavutil/half2float.h b/libavutil/half2float.h
index 5af4690cfe..10b6fef4e6 100644
--- a/libavutil/half2float.h
+++ b/libavutil/half2float.h
@@ -21,6 +21,12 @@
 
 #include <stdint.h>
 
+typedef struct half2float_tables {
+    uint32_t mantissatable[3072];
+    uint32_t exponenttable[64];
+    uint16_t offsettable[64];
+} half2float_tables;
+
 static uint32_t convertmantissa(uint32_t i)
 {
     int32_t m = i << 13; // Zero pad mantissa bits
@@ -37,41 +43,39 @@ static uint32_t convertmantissa(uint32_t i)
     return m | e; // Return combined number
 }
 
-static void half2float_table(uint32_t *mantissatable, uint32_t *exponenttable,
-                             uint16_t *offsettable)
+static void init_half2float_tables(half2float_tables *t)
 {
-    mantissatable[0] = 0;
+    t->mantissatable[0] = 0;
     for (int i = 1; i < 1024; i++)
-        mantissatable[i] = convertmantissa(i);
+        t->mantissatable[i] = convertmantissa(i);
     for (int i = 1024; i < 2048; i++)
-        mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL);
+        t->mantissatable[i] = 0x38000000UL + ((i - 1024) << 13UL);
     for (int i = 2048; i < 3072; i++)
-        mantissatable[i] = mantissatable[i - 1024] | 0x400000UL;
-    mantissatable[2048] = mantissatable[1024];
+        t->mantissatable[i] = t->mantissatable[i - 1024] | 0x400000UL;
+    t->mantissatable[2048] = t->mantissatable[1024];
 
-    exponenttable[0] = 0;
+    t->exponenttable[0] = 0;
     for (int i = 1; i < 31; i++)
-        exponenttable[i] = i << 23;
+        t->exponenttable[i] = i << 23;
     for (int i = 33; i < 63; i++)
-        exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL);
-    exponenttable[31]= 0x47800000UL;
-    exponenttable[32]= 0x80000000UL;
-    exponenttable[63]= 0xC7800000UL;
+        t->exponenttable[i] = 0x80000000UL + ((i - 32) << 23UL);
+    t->exponenttable[31]= 0x47800000UL;
+    t->exponenttable[32]= 0x80000000UL;
+    t->exponenttable[63]= 0xC7800000UL;
 
-    offsettable[0] = 0;
+    t->offsettable[0] = 0;
     for (int i = 1; i < 64; i++)
-        offsettable[i] = 1024;
-    offsettable[31] = 2048;
-    offsettable[32] = 0;
-    offsettable[63] = 2048;
+        t->offsettable[i] = 1024;
+    t->offsettable[31] = 2048;
+    t->offsettable[32] = 0;
+    t->offsettable[63] = 2048;
 }
 
-static uint32_t half2float(uint16_t h, const uint32_t *mantissatable, const uint32_t *exponenttable,
-                           const uint16_t *offsettable)
+static uint32_t half2float(uint16_t h, const half2float_tables *t)
 {
     uint32_t f;
 
-    f = mantissatable[offsettable[h >> 10] + (h & 0x3ff)] + exponenttable[h >> 10];
+    f = t->mantissatable[t->offsettable[h >> 10] + (h & 0x3ff)] + t->exponenttable[h >> 10];
 
     return f;
 }
-- 
2.34.1



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